Re: [xmlvm-users] Using categories vs. encapsulation in Objective-C compat-lib

[Arno P. <ar...@pu...>]

I wanted to comment on your comment.  :-)  There is never the 'optimal' 
solution as you have pointed out. I recently came across this Java code 
that someone tried to cross-compile:

... = new Stack<String>() { ...override toString() };

This doesn't work with our way of defining a category to NSMutableArray 
because this Cocoa class cannot be subclassed!

Anyways, I wanted to make one more point I didn't mention in my original 
reply. Apart from compiling OpenJDK we are also working on a new code 
generation backend for C/C++. Eventually I would like to deprecate the 
Objective-C backend for two reasons: first of all C/C++ is much more 
portable across different smartphone platforms. Objective-C only works 
on the iPhone, so with a C/C++ backend we can more easily target other 
smartphones in the future. Note that iPhone also supports C/C++.

Second reason: Java is a statically typed language and Objective-C is a 
dynamically typed language. When cross-compiling a statically typed 
language to a dynamically typed language, you cannot do very many 
optimizations. Since we have this information on the Java side, it would 
be possible to map many Java methods to simple C functions whose 
invocation would be much more runtime efficient than a dynamic method 
dispatch in Objective-C.

Well, this is ongoing work and won't happen in quite some time. But I do 
believe it is the right way to go.

Arno


On 7/12/10 10:33 AM, Panayotis Katsaloulis wrote:
>
> On 11 Ιουλ 2010, at 2:47 μ.μ., Arno Puder wrote:
>
>> …
>> We are currently working on cross-compiling the original JRE classes
>> from OpenJDK. For one, it would give us instant 100% compatibility and
>> the issues you have described would also be resolved. Note that this is
>> ongoing work and will take some time to complete.
>>
>> Arno
>
>
> I have a comment on this.
> I think that even if it is useful and "quick", direct using of java objects found in the JDK is not a good idea.
> JDK is optimized for various versions, situations and platforms, and uses many objects from many other packages.
> Moreover most of the library is written in JAVA itself (and for a good reason).
>
> At least for the iOS port I believe that this is not an optimum solution. Most calls can be directly mapped to obj-c selectors and there is no need to implement them just to keep 100% java compatibility. I believe the pathway that was followed up to now, to map as much methods as possible and implement anew only tiny bits, is the best approach.
>
> Panayotis
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